Circle.cs

using System.Threading.Tasks;
using System.Xml;
using SkiaSharp;
using Waher.Layout.Layout2D.Model.Attributes;
 
namespace Waher.Layout.Layout2D.Model.Figures
{
    public class Circle : FigurePoint
    {
        private LengthAttribute radius;
        private float r;
 
        public Circle(Layout2DDocument Document, ILayoutElement Parent)
            : base(Document, Parent)
        {
        }
 
        public override string LocalName => "Circle";
 
        public LengthAttribute RadiusAttribute
        {
            get => this.radius;
            set => this.radius = value;
        }
 
        public override Task FromXml(XmlElement Input)
        {
            this.radius = new LengthAttribute(Input, "radius", this.Document);
            return base.FromXml(Input);
        }
 
        public override void ExportAttributes(XmlWriter Output)
        {
            base.ExportAttributes(Output);
 
            this.radius?.Export(Output);
        }
 
        public override ILayoutElement Create(Layout2DDocument Document, ILayoutElement Parent)
        {
            return new Circle(Document, Parent);
        }
 
        public override void CopyContents(ILayoutElement Destination)
        {
            base.CopyContents(Destination);
 
            if (Destination is Circle Dest)
                Dest.radius = this.radius?.CopyIfNotPreset(Destination.Document);
        }
 
        public override async Task DoMeasureDimensions(DrawingState State)
        {
            await base.DoMeasureDimensions(State);
 
            EvaluationResult<Length> RadiusLength = await this.radius.TryEvaluate(State.Session);
            if (RadiusLength.Ok)
            {
                State.CalcDrawingSize(RadiusLength.Result, ref this.r, true, (ILayoutElement)this);
                this.Width = this.ExplicitWidth = this.Height = this.ExplicitHeight = 2 * this.r;
            }
            else
                this.defined = false;
 
            if (this.defined)
            {
                this.IncludePoint(this.xCoordinate - this.r, this.yCoordinate);
                this.IncludePoint(this.xCoordinate + this.r, this.yCoordinate);
                this.IncludePoint(this.xCoordinate, this.yCoordinate - this.r);
                this.IncludePoint(this.xCoordinate, this.yCoordinate + this.r);
            }
        }
 
        public override async Task Draw(DrawingState State)
        {
            if (this.defined)
            {
                SKPaint Fill = await this.TryGetFill(State);
                if (!(Fill is null))
                    State.Canvas.DrawCircle(this.xCoordinate, this.yCoordinate, this.r, Fill);
 
                SKPaint Pen = await this.TryGetPen(State);
                if (!(Pen is null))
                    State.Canvas.DrawCircle(this.xCoordinate, this.yCoordinate, this.r, Pen);
            }
        
            await base.Draw(State);
        }
 
        public override void ExportStateAttributes(XmlWriter Output)
        {
            base.ExportStateAttributes(Output);
 
            this.radius?.ExportState(Output);
        }
    }
}